Like many commenters here, I'm not sure I can agree with the author's position. Plenty of in-browser apps go awry, but that's most often because the tools people start using (notably jQuery) just don't work well once you have a large collection of UI components on the page.

That said, the bulk of Google's web applications, for instance, are not written in GWT or Dart, but rather in JavaScript using Closure Library, and compiled using the Closure compiler. So I don't think the answer here is to not use JavaScript (although I can understand why people at Adobe would argue for that), but rather to use tools like Closure or Angular that make the process more straightforward.